To meet the demand for wireless data traffic having increased since deployment of 4G communication systems, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (COMP), reception-end interference cancellation and the like.
In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
Generally, handover (HO) is an important procedure in a cellular transmission as it enables service continuity within a same radio access technology (RAT) or across different RATs. In existing systems, a hard HO and a soft HO are available for a UE to switch from a source base station to a target base station; thereby, maintaining the continuity of service. In soft HO, the UE receives downlink data from multiple BS while the HO procedure is being followed i.e., during the time of HO; the UE has the radio link with both the source base station and the target base station. If the UE is connected to two (or multiple) BSs during the HO then the UE will receive complete code word from the source and target base station as indicated in FIG. 1A.
In hard HO, the UE has to break the radio link with the source base station before the new radio link can be established with the target base station i.e., at any point of time the UE has the radio link with only one base station as indicated in FIG. 1B. In the hard HO, particularly in Global System for Mobile Communications (GSM), Long Term Evolution (LTE) and inter-frequency HO in Code division multiple access (CDMA) based technologies, when the UE meets the HO condition then the UE will transmit measurement reports of a signal strength of the neighbor BS whose signal strength is improving when compared to the source BS. Based on the reports, the source BS will provide the radio link details of the target BS to the UE. The UE will break the link with the source BS and establish the new link with the target BS. The hard HO of Long Term Evolution (LTE) is one of the causes for ping-pong effect that leads to an overhead in signaling. To mitigate ping-pong effect, one possible solution is to have a joint transmission during HO. The joint transmission of a complete code word from the serving and target base stations during the HO will increase the usage of scarce spectrum resources and decrease the overall cell spectral efficiency.
The joint processing from the multiple BSs can be in the form of dynamic point switching (DPS); wherein, only one BS can transmit to the UE at a given time instant or joint transmission (JT); wherein, all the BSs in the transmission set transmit the same data to the UE simultaneously. In both the modes of transmissions, data packet for the UE is available at all the BSs in the transmitting set. The JT is more attractive in light of the link fragility in mm-wave systems. Due to the link fragility, soft handover will be preferred in comparison to hard handover. In currently known soft handover schemes, complete data is transmitted by a plurality of BSs that participate in the HO procedure. Thus, there is an overhead both during transmission of data as well as during HO. Considering the link fragility of mm-wave systems and the necessity for small cells, the number of handovers will increase. Consequently, due to the overhead during handover and increased number of handovers, the system throughput will decrease significantly.
The above information is presented as background information only to help the reader to understand the present disclosure. Applicants have made no determination and make no assertion as to whether any of the above might be applicable as Prior Art with regard to the present application.